Role of Drugs in Behavioural Therapy

Introduction

In most cases of feline behaviour problems, environmental modification alone is enough to resolve the problem. Anxiety, fear and stress can be treated effectively using conventional methods such as desensitisation and counter-conditioning, or by allowing the cat to perform avoidance behaviour.

The basis of using psychoactive medication in the treatment of behavioural problems in cats is to alter emotional and behavioural responses to situations and events in order to promote adaptation. For example:

• Reducing anxiety so that the individual is less stressed, better able to make better use of its environment and interact socially.
• Reducing compulsive motivation so that the cat is able to perform a wider range of normally motivated behaviours.
• Reduce impulsiveness
• Reduce specific fear, so that the cat is less avoidant of fearful stimuli and better able to become desensitised.

These are generally the more severe cases in which the emotional state of an animal interferes with the implementation of behaviour modification and the use of medication can be justified .

Any underlying medical cause for problem behaviours should be ruled out before any pharmacological intervention.

Use of Drugs in Animals

It must be remembered that all of the current psychoactive medications licensed for use in humans have been discovered using testing in animal models of anxiety, fear, phobia, compulsion etc. Almost all have been tested in small animal species that are kept as pets, particularly rodents and dogs. This does not mean that clinically effective doses are known for these species, or even that equivalent behaviour disorders are naturally occurring in them. However, it has provided support for the use of psychoactive medications in veterinary patients which has ultimately led to licensing of some products for veterinary use.

Typical situations in which psychoactive medication can be a useful adjunct to behavioural modification techniques include:

• When fear or anxiety are very intense:
• Making therapy difficult or dangerous, bearing in mind the risk of disinhibition.
• Where conditions eliciting fear or anxiety are unavoidable in normal life.
• Where the animal is suffering as a result of chronic anxiety or repeated fearful experiences.

• When the prognosis is likely to be improved:

• Condition is longstanding or severe and therefore less likely to respond to behaviour modification.
• Where distraction is difficult (e.g. severe stereotypy/compulsion).
• If speed of recovery is critical (threat of legal action, eviction etc).

When considering whether to incorporate psychoactive drugs into a treatment program for problem behaviour, there are several conditions which should be met:

1. A sensible diagnosis should be arrived at.
2. The clinician should have knowledge of the neurochemistry relating to the condition.
3. The clinician should have an awareness of the supposed mechanism of action of the selected drug.
4. The clinician must have a clear understanding of any potential side effects.
5. Both the clinician and owner need to have a clear idea of how the selected medication will change the behavioural pattern which is a problem. Owners must be informed of potential side effects and warn the clinician if there is even the slightest problem. As medication for behavioural conditions is often long-term, owner awareness and compliance is very important.

These guidelines are important to ensure the correct use of drugs within the behavioural field as administration of medication is always long-term in comparison to most other drug use and they help the owner take-part in the process of evaluation as to the effectiveness of the drug prescribed .

Before any drug is prescribed, a comprehensive behavioural and medical history should be compiled. In older animals, those suffering from cardiac or endocrine disorders as well animals which are already on treatments for any existing conditions, extreme care should be taken. All animals should undergo a complete physical examination as well as blood tests. For a cat, a complete blood count, serum biochemistry profile and urinalysis, ideally with culture and sensitivity form a complete laboratory work up . In addition in older cats thyroid levels should be tested and if cardiac disease is a worry a lead II ECG should be performed to exclude the existence of cardiomyopathy. This also provides a baseline for cardiac side effects of medications to be measured against .

Combining behavioural therapy with medication

Depression, anxiety, fear and phobia may be associated with genuine long-term neurotransmitter and synaptic changes in the CNS, but these changes are reversible through new learning in combination with medication.

An example of a typical approach to fear using behavioural modification would be:

• Identify all fear provoking stimuli
• Identify the threshold for the fear response (e.g. distance from target)
• Establish a gradient of stimuli (distance, appearance of person etc). This should be used to understand approach-avoidance behaviour.
• Control the pet’s environment to reduce stress (prevent exposure in uncontrolled situations)
• Desensitisation and counter-conditioning: desensitise using gradually increasing exposure to fear-eliciting stimulus at a level below which fear is evoked, use counter-conditioning to replace fear with another incompatible emotional response to the same stimulus.

In such a case, medication that reduces the intensity of fear, and increases exploratory behaviour would facilitate desensitisation and counter-conditioning.

A similar approach is used for anxious behaviour:

• Identify contexts and situations that elicit anxiety.
• Desensitise and counter-condition contexts and situations that elicit anxiety.

In such a case, an anxiolytic medication, such as an SSRI drug, can be used to facilitate desensitisation and counter-conditioning. This will reduce hyper vigilance and arousal so that the cat settles more quickly in the environment.

In the human behaviour field, psychoactive medication is extensively used in combination with cognitive and behavioural approaches to treat problems relating to fear, phobia and anxiety. In the veterinary behaviour field there are only a very few drugs which have been properly tested under controlled trials. For the majority of other medications there is minimal available data and information is extrapolated from use in the field of human psychiatry. When using drugs which are not licensed for veterinary use, it is important to consider that drug metabolism and effects vary between species. .